NHK has learned that police in Japan have raided a number of seafood traders who are suspected of selling clams illegally imported from North Korea.

Sources close to the investigation say dozens of places were raided on Wednesday, including seafood traders in Yamaguchi, Fukuoka, Ibaraki and Saitama prefectures and Tokyo.

Sources say the traders are suspected of fraudulently labeling North Korean clams as Japanese products, violating the Unfair Competition Prevention Act.

Police also say the alleged illegal trades may have created a flow of money into North Korea through a domestic network involving the traders.

The Japanese government independently bans exports to and imports from North Korea as part of its sanctions against Pyongyang.

The sources say the clams were allegedly brought to Japan via China, South Korea, or through other routes.

Officials suspect that the clams were labeled as Russian products during the importing process so that they would not to be rejected under the sanctions.